This invention relates generally to a method of inhibiting the growth of organisms on a marine structure. In particular, this invention relates to the use of dihydropyridazinone and pyridazinone compounds as marine antifouling agents.
Marine antifouling agents are used commercially to prevent growth of organisms on marine structures. Tributyltin oxide and other organotins have been the major marine antifouling agents in use for many years. There is currently much concern over the effects of tin on marine environments. For example, high levels of tin in harbor waters have been linked to shell deformation in some bivalve species, such as oysters.
Some organic compounds have been suggested as marine antifouling agents. For example, U.S. Pat. No. 5,071,479 (Gruening) discloses the use of 3-iodopropargyl N-butyl carbamate as a marine antifouling agent. These types of compounds have not achieved commercial prominence because they do not meet the same performance requirements as tin based antifouling agents.
EP 478195 (Egan, et al.) discloses certain dihydropyridazinone and pyridazinone compounds as medical and agrochemical fungicides. EP 478195 also discloses these compounds to be useful as wood preservatives effective against wood decay organisms. Such wood decay organisms are fungi. There is no disclosure of these compounds as marine antifouling agents.
The organisms controlled by agricultural fungicides or wood preservatives are very different from those controlled by marine antifouling agents. Marine antifouling agents control multicellular organisms and slime, such as diatoms, barnacles, hydroids, grassy brown felt algae, and the like. The effectiveness of agrochemical fungicides useful in combating fungi on plants cannot be used to predict the effectiveness of these compounds as marine antifouling agents in sea water and brackish water.
The problem addressed by this invention is to provide marine antifouling agents having increased performance and little or no harmful effects on marine environments.